Renewable inclosed fuse.



w. J. MORGAN. RENEWABLE iNCLOS ED FUSE.

APPLICATION FILED JULY 2, 19M.-

Patnted July 17, 1917.

2 SHEETS-SHEET I.

llllllllllllllllllllllln W. J. MORGAN.

RENEWABLE INCLOSED FUSE.

APPLICATION FILED JULY 2.1914. 1,234,100.

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WILLIAM J. MORGAN, OF ST. LOUIS, MISSOURI.

RENEWABLE INGLOSED FUSE.

Specification of Letters Patent.

Patented July 17, 1917.

Application filed July 2, 1914. Serial No. 848,523.

T 0 all 1c]: 0222 it may concern Be it known that 1, Wm J. MORGAN,

' a citizen of the United States, residingat refers particularly (although not exclusively) to fuses of the so-called knife-blade tv (S ne of the disadvantages of renewable inclosed safety fuses which have heretofore been used has been that after the original fusible link placed in the fuse by the manufacturer has been blown it was possible to insert in the fuse casing and fasten to the fuse terminals a link which might be of greater capacity than that for which the fusewas designed. The fusible link commonly used in the knife-blade type of safety fuses ordinarily consists of a fiat strip or a plurality of fusible wires having a single flat contact member on each end of the fusible element consisting of such a plurality of wires. The ordinary method of attaching the fusible-element to the knife-blade terminals extending into the ends of the casing has been by fastening the ends of the fusible element to the terminals by the use of bolts. screws. or the like. It will be evident that by this prior method of fastening the fusible element to the terminals a fuse link of any size could be readily attached to the terminals. and inasmuch as the capacity of the fusible element is governed by its cross-sectional area it was thus possible to place in a 100-ampere casing for example a fuse link having a capacity of 150 amperes, thus causing the fuse to carry a current under circumstances in which it was originally intended that the fuse should open the electrical circuit.

It is the object of my invention to provide means by which a fuse link of a greater capacity than that for which the fuseis designed can notbe attached to the terminals extending into the ends of the casing. and in order to accomplish this result I provide in connection with each terminal a link-receiv ing space of dimensions just sufficient to receive the ends of a link of the capacity for which the fuse was designed. Usually flat fusible elements of different capacities have different thicknesses of metal at their ends, so that ordinarily it is sufiicient to control the thickness of the ends of the links which may be attached to the fuse terminals, but, if desired. 1 may control both the thickness and width of the ends of a flat fuse link, or the diameter of a link having round ends. A further object of my invention consists in the use of an insulating connecting member fastened to the inner ends of the terminals by which the latter are maintained at a fixed distance from each other.

These and other advantages of my invention will be more readily understood by reference to the accompanying drawings, in

which Figure 1 is a longitudinal section through my improved renewable inclosed safety fuse;

Fig. 2 is a longitudinal section similar to Fig. 1 but taken at the line :2 :2 of Fig. 1;

Fig. 3 is a transverse section taken on the line 3-3 of Fig, 1;

Fig. -l is a perspective of the insulating connector;

Fig. 5 a longitudinal section through my improved fuse showing a modified form of. connector and fuse link;

Fig. 6 is a longitudinal section taken on the line 6-6 of Fig. 5;

Fig. 7 is a transverse section taken on the line 7-7 of Fig.6; and

Fig. 8 is a perspective of the connector shown in Figs. 5, 6 and 7. V

My inclosed safety fuse has a casing 10 preferably of fiber or other suitable insulating material. Extending into the ends of the casing 10 are the terminals 11, which pass through suitable apertures in the caps 12 which are held in position by means of the screws 13. As most clearly shown in Fig. 2,-the connector H, of insulating material, extends between the inner ends of the terminals 11, and is fastened thereto by means of rivets 15. The connector 11 is provided with a recessed receiving space 16 near each end.

A fusible link 17 which is preferably flat, is provided near its ends with the notches 18. The receiving space 16 formed in the connector 1% and immediately adjacent to the surface of the inner end of each terminal 11 is of just suflicient thickness to re ceive the end of the link 17 of a predetermined capacity. A threaded rivet 19 extends from each terminal into a recess 20 formed in the connector 14, and the threaded end of this rivet is provided with a nut 21 having therein the slot 22' so that this nut may be adjusted in position on inserting ascrew driver through the aperture in the connector 11. The link 1? is secured in position by inserting its ends in the receiving spaces 16, the edge of the link resting against the walls 21 of the receiving spaces 16 and the notches 18 receiving the rivets 19. On tightening the nuts 21 the ends of the link 17 are securely held in position againstthe surfaces of the terminals 11.

On blowing the fusible link 14' the latter may readily be replaced by a new link on first removing the caps 12 and then withdrawing from the casing 10 the terminals 11 and the connector 11 which mechanically joins the two terminals to each other. The

i nuts 21 are then loosened. the ends of the fusible link 17 are removed. and a new link placed in position. after which the terminals and connector with the attached link are again placed position within the casing, and the caps 12 are fastened in place. It will be evident that in this way the link 17 may be readily renewed. while at the same time, on account of the limited thickness of the receiving space 16 it is impos ible to place a link 'in position which is of greater thickness and, therefore. greater capacity, than that for which the fuse is designed.

I prefer to use in my improved fuse shredded asbestos or other suitable packing gmaterial 21 near the ends of the casing and immediately adjacent to the caps 12 m that V on blowing of the fuse the gases which are expelled through the vents 25 in the caps 12 may be retarded in their pas age'from the interior of the casing.- I may also employ a non-conducting filling of asbestos. lime, plasterof Paris. or the like. within the casing 10 if desired, but the use of such filling constitutes no partof my invention. and the filling may be entirely omitted if desired.

In the modified construction illustrated in Figs. 5 to S. inclusive. the various parts are similar to those shown in Figs. 1 to i. inclusive. with the exception of the fusible link and the connector. The connector 11* is providedwithihe recesses 16 near its ends. These recesses are bounded on three sides by the walls 21*, 26 and 27. be apparentthat when the connector L1 is attached to the terminals 11 by means of the rivets 15 the recesses 16 are open only on their inner ends. The threaded rivet 19* extends from each terminal 11 into the re cess 20* formed at each end of the connector It will thus '11, the threaded end of this rivet being provided with a nut 21 having therein the slot 22 The link 17 is provided at its ends with the longitudinally-disposed slots 18. 'Ihc'link is inserted in position by bending it and slipping its ends into the recesses 16= of the connector 11". each of the notches 1S receiving the rivet 19*. In order tokhold the ends of the link 17 in position the nuts 21 are screwed home by inserting a suitable tool through the apertures 23.

Itwill be evident that by the construction described in connection with Figs. 5 to 8, inclusive not only the thickness but also the width of the ends of the fusible link which may be attached to the terminals 11 is controlled, and a fusible link having ends either of greater thickness or of greater width than the thickness and width of the recesses 16 cannot be inserted in these recesses and so attached to the terminals.

I may also employ various mechanical equivalents for the purpose of obtaining a receiving space of predetermined size in connection with each of the terminals. .It will thus be understood by those skilled in the art that many changes could be made in the detailed construction of the various parts which I have described without de parting from the spiritor scope of my invention, as defined in the appended claim.

' What- I claim is:

In an inclosed fuse. the combination of an inclosing casing, terminals extending into the ends of said casing. an insulating connector extending between and fastened to said terminals and forming at each terminal a link-receiving space of predetermined thickne$ adjacent to the face of said terminal. said connector also having a fastening receiving recess communicating with said link-receiving space adjacentto the face of each terminal and an aperture of smaller cross-sectional area than said recess and extending therefrom to the exterior of said connector. link-fastening means within said reces and of larger size than said aperture. and a link having its ends in said hnkreceiving spaces and broughtinto engagement with the faces of said terminals by said link-fastening means.

In witness whereof, I hereunto subscribe my name this 29th day of J1me. A. D. 1914.

LIAM J. MORGAN.

Witnesses: 

